Bobber motorcycles are typically stripped down custom motorcycles featuring a minimalistic design having all superfluous parts removed to reduce weight and obtain the “bobber style”. Many bobber motorcycles feature a hard tail frame, i.e. with no rear suspension, and have no airboxes, ABS and batteries which saves a lot of space in the central area of the motorcycle and helps to give its simplistic, “open” look. In addition, one of the typical characteristics of a bobber motorcycle is a relatively low and far back seat position, which is permitted by the lack of rear suspension.
In order to reduce the amount of parts in a bobber motorcycle, it is often not designed with a high focus on ergonomics. Style and look of a bobber is very important but it is also desirable to achieve this style without compromising function. This leads to technical challenges which must be overcome to achieve both the bobber style and a safe and ergonomic design with good riding performance, with original equipment needed to meet regulations, e.g. homologation requirements.
It is difficult to keep both motorcycle wheels on the ground at all times without a rear suspension. Therefore, in order to meet the safety requirements of a modern motorcycle, a rear suspension unit (RSU) needs to be included. Having rear suspension not only provides a better riding performance and higher standard of safety, but is also more comfortable to ride. A RSU takes up a significant amount of space on a motorcycle, which, as mentioned above, is unwanted in a bobber due to the minimalistic design aspirations. Previous designs of a RSU on custom bobber motorcycles include positioning the rear suspension underneath the frame or along either side of the wheels but these either take up a lot of space or disrupt the appearance of a hard tail frame. In addition, taking into account the restricted space available, a RSU must meet a required suspension performance to provide a relatively smooth ride.
In order to meet regulatory requirements, an airbox also needs to be included. The air filter, which sits inside the airbox has to meet certain size requirements, which link directly to the lifetime of the filter. Simplistically, the larger the area of the filter, the longer the filter will last. This in turn dictates the frequency of service intervals, which directly translates into the maintenance cost of the motorcycle. Hence, a bigger filter is more desirable for the customer, because it means that the motorcycle will need to be serviced less frequently. One way that a bigger filter surface area is achieved is by increasing the volume of the airbox.
The most common practice for a bobber is to have a solo seat mounted above a hard tail frame. The seat is usually hinged at the front and then supported at the back using springs. This design does not allow for adjustability of the riding position, which in turn limits the ergonomic range of the motorcycle.
The present invention has therefore been devised with the foregoing in mind. The invention seeks to overcome or ameliorate at least one of the disadvantages of the prior art, or provide a useful alternative.